Recent developments on micrometric fission chambers for high neutron fluxes

ISBN 9781424452071International audiencewith the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world

Tunable magnetic properties of arrays of Fe(110) nanowires grown on kinetically-grooved W(110) self-organized templates

We report a detailed magnetic study of a new type of self-organized nanowires disclosed briefly previously [B. Borca et al., Appl. Phys. Lett. 90, 142507 (2007)]. The templates, prepared on sapphire wafers in a kinetically-limited regime, consist of uniaxially-grooved W(110) surfaces, with a lateral period here tuned to 15nm. Fe deposition leads to the formation of (110) 7 nm-wide wires located at the bottom of the grooves. The effect of capping layers (Mo, Pd, Au, Al) and underlayers (Mo, W) on the magnetic anisotropy of the wires was studied. Significant discrepancies with figures known for thin flat films are evidenced and discussed in terms of step anisotropy and strain-dependent surface anisotropy. Demagnetizing coeffcients of cylinders with a triangular isosceles cross-section have also been calculated, to estimate the contribution of dipolar anisotropy. Finally, the dependence of magnetic anisotropy with the interface element was used to tune the blocking temperature of the wires, here from 50K to 200 K

SPIRAL2 RFQ prototype - First results

JACoW web site MOPCH103International audienceThe SPIRAL2 RFQ is designed to accelerate either 5 mA deuteron beam (Q/A=1/2) or a 1 mA of q/A=1/3 particle up to 0.75 MeV/A at 88 MHz. It is a CW machine which has to show stable operation, provide the required availability and reduce losses to a minimum in order to minimize the activation constraints. Extensive modelisation was done to ensure a good vane position under RF. The prototype of this 4-vane RFQ was built and tested in INFN-LNS Catania and then in IN2P3-LPSC Grenoble. It allowed us to measure the vacuum quality, the RF field by X-ray measurements, the cavity displacement and the real vane displacement during the RF injection. Different techniques were used, including an innovative CCD measurement with a 0.8 μm precision. This paper outlines the different results

Improvements in the determination of ISS Ca II K parameters

Measurements of the ionized Ca II K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a ground-based proxy to model the solar ultraviolet flux variation that may influence the Earth's climate. Full disk images of the Sun in Ca II K have been available from various observatories for more than 100 years and latter synoptic Sun-as-a-star observations in Ca II K began in the early 1970s. One of these instruments, the Integrated Sunlight Spectrometer (ISS) has been in operation at Kitt Peak (Arizona) since late 2006. The ISS takes daily observations of solar spectra in nine spectra bands, including the Ca II K and H line s. We describe recent improvements in data reduction of Ca II K observations, and present time variations of nine parameters derived from the profile of this spectral line

Gratitude mediates quality of life differences between fibromyalgia patients and healthy controls

Purpose: Despite a growing literature on the benefits of gratitude for adjustment to chronic illness, little is known about gratitude in medical populations compared to healthy populations, or the degree to which potential deficits in gratitude might impact quality of life. The purpose of the present study was to (1) examine levels of gratitude and quality of life in fibromyalgia patients and healthy controls and (2) consider the role of gratitude in explaining quality of life differences between fibromyalgia patients and healthy controls. Methods: Participants were 173 fibromyalgia patients and 81 healthy controls. All participants completed measures of gratitude, quality of life, and socio-demographics. Results: Although gratitude was positively associated with quality of life, levels of gratitude and quality of life were lower in the fibromyalgia sample relative to the healthy controls. This difference in gratitude partially mediated differences in quality of life between the two groups after controlling for socio-demographic variables. Conclusions: Our findings suggest that gratitude is a valuable positive psychological trait for quality of life in people with fibromyalgia. Interventions to improve gratitude in this patient population may also bring enhancement in quality of life

Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos

The static electromagnetic properties of the $W$ boson, $\Delta \kappa$ and $\Delta Q$, are calculated in the SU_L(3)} \times U_X(1) model with right-handed neutrinos. The new contributions from this model arise from the gauge and scalar sectors. In the gauge sector there is a new contribution from a complex neutral gauge boson $Y^0$ and a singly-charged gauge boson $Y^\pm$. The mass of these gauge bosons, called bileptons, is expected to be in the range of a few hundreds of GeV according to the current bounds from experimental data. If the bilepton masses are of the order of 200 GeV, the size of their contribution is similar to that obtained in other weakly coupled theories. However the contributions to both $\Delta Q$ and $\Delta \kappa$ are negligible for very heavy or degenerate bileptons. As for the scalar sector, an scenario is examined in which the contribution to the $W$ form factors is identical to that of a two-Higgs-doublet model. It is found that this sector would not give large corrections to $\Delta \kappa$ and $\Delta Q$.Comment: New material included. Final version to apppear in Physical Review

Congenital diaphragmatic hernia and exercise capacity, a longitudinal evaluation

Objective: Children with congenital diaphragmatic hernia (CDH) suffer from long-term pulmonary morbidity. Longitudinal data of exercise capacity in these children are lacking. We hypothesized that exercise capacity would be impaired in children with CDH and deteriorates over time. We evaluated exercise capacity and its determinants in CDH patients longitudinally until 12 years of age. Design: Prospective longitudinal follow-up study in tertiary university hospital. Patients: One hundred and fourteen children with CDH born between 1999 and 2012. Methods: Exercise capacity was evaluated using the Bruce treadmill-protocol at the ages of 5, 8, and 12 years. Primary outcome parameter was standard deviation score (SDS) of maximal endurance time. Data were analyzed by using linear mixed models. Results:A total of 107 children (30 treated with extracorporeal membrane oxygenation [ECMO]) performed 191 reliable exercise tests. At ages 5, 8, and 12 years, the mean (95%CI) SDS endurance time was −0.44 (−0.65 to −0.24); −1.01 (−1.23 to −0.78); −1.10 (−1.40 to −0.80), respectively, all less than zero (P < 0.001). Exercise capacity declined significantly over time irrespective of ECMO-treatment (5-12 years: non-ECMO P = 0.015; ECMO P = 0.006). Duration of initial hospital stay and diffusion capacity corrected for alveolar volume were associated with SDS endurance time (P < 0.001 and P = 0.039). Conclusions: In CDH patients exercise capacity deteriorates between 5 and 12 years of age, irrespective of ECMO-treatment. CDH patients may benefit from long-term assessments of exercise capacity with timely intervention

Big Bang Baryogenesis

An overview of baryogenesis in the early Universe is presented. The standard big bang model including big bang nucleosynthesis and inflation is breifly reviewed. Three basic models for baryogenesis will be developed: The ``standard" out-of-equilibrium decay model; the decay of scalar consensates along flat directions in supersymmetric models; and lepto-baryogenesis, which is the conversion of a lepton asymmetry into a baryon asymmetry via non-perturbative electroweak interactions.Comment: 36 pages, LaTeX, UMN-TH-1249, Lectures given at the 33rd International Winter School on Nuclear and Particle Physics, ``Matter Under Extreme Conditions", Feb. 27 - March 5 1994, Schladming Austri

Dynamical Left-Right Symmetry Breaking

We study a left--right symmetric model which contains only elementary gauge boson and fermion fields and no scalars. The phenomenologically required symmetry breaking emerges dynamically leading to a composite Higgs sector with a renormalizable effective Lagrangian. We discuss the pattern of symmetry breaking and phenomenological consequences of this scenario. It is shown that a viable top quark mass can be achieved for the ratio of the VEVs of the bi--doublet $\tan\beta\equiv\kappa/\kappa'$ =~ 1.3--4. For a theoretically plausible choice of the parameters the right--handed scale can be as low as $\sim 20 TeV$; in this case one expects several intermediate and low--scale scalars in addition to the \SM Higgs boson. These may lead to observable lepton flavour violation effects including $\mu\to e\gamma$ decay with the rate close to its present experimental upper bound.Comment: 51 pages, LaTeX and uuencoded, packed Postscript figures. The complete paper, including figures, is also available via WWW at http://www.cip.physik.tu-muenchen.de/tumphy/d/T30d/PAPERS/ TUM-HEP-222-95.ps.g